Introduction: 10.00 V Voltage Reference to Check Meters for Accuracy
Was going through my parts box and found this IC LT1021 - when I checked on the web found out that it was a voltage reference chip. So decided to convert to a voltage reference device to check the many cheap digital panel meters I had and also to calibrate my analog meters. The build is quite simple as you can see in the circuit diagram and I had the parts to build one.
I decided to power it from a USB 5V power supply so would need to increase the voltage to about 15V from the 5V therefore added an upconverter. The final diagrammatic circuit is shown in the last figure.
Step 1: Preparing the Altoids Case for the Electronics
I cut two holes for the 3-way binding posts on end end of the tin and a rectangular cut out for the USB A socket. And a single hole in the bottom of the tin for the overcurrent LED.
I test fit the parts to make sure they fit.
Step 2: Connecting the Electronic Parts
Decided to build the system in an Altoids can on a perforated board.
Added the USB A socket first to the perf board, followed by the other components including the voltage converter board to the perf board. Used simple point to point wiring.
Step 3: Assembly
Connected the electronics board (wrapped in shipping tape) to the binding posts, filled it with Styrofoam peanuts to wedge the board in and hopefully prevent temperature fluctuations which may impact the accuracy.
Filled gaps with epoxy putty and sanded those smooth.
Added magnet to the inside of the Altoids tin lid so that I can attach the voltage reference to any steel surface.
Had added a wood plywood panel to the top of this unit.
And hand lettered the labels. Know they don't look that professional. Will go back and create better labels as I now have a laser cutter.
Step 4: Nice Little Addition to My Tool Kit!
The voltage reference could provide 60 mA, enough to light a small incandescent bulb.
I tested the main multimeter that I use routinely and it was way off. Had not noticed that the battery was low on it. Replaced the 9V battery and it read the 10.00V. Also tested the other meters, they were about 1-3% off. Good to know.